Studies on polymer-metal interfaces. 2. Competitive adsorption between oxygen- and nitrogen-containing functionality in model copolymers onto metal surfaces

The competitive adsorption behavior between oxygen- and nitrogen-containing functionality in poly(methyl methacrylate-co-2-vinylpyridine) (MMA2VP) and poly(methyl methacrylate-co-4-vinylpyridine) (MMA4VP) random copolymers on to alumina substrate was investigated. The adhesive strength of both the MM A2VP/alumina and MMA4VP/alumina systems increased with increasing vinylpyri dine (VP) content in the copolymers, and the effect was more prominent for the MMA4VP/alumina system. Analysis of the reflection-absorption infrared s pectroscopy shows that the carbonyl functional groups in MMA2VP and MMA4VP interact specifically with alumina while the pyridine rings in VP units are oriented more vertically to alumina surface than carbonyl groups. Results from X-ray photoelectron spectroscopy (XPS) reveal that both the nitrogen-c ontaining functionalities in 2VP or 4VP units and the oxygen-containing fun ctionality in MMA unit interact specifically with alumina surface. The quan titative analysis of XPS spectra indicates that the nitrogen-containing fun ctionality adsorbs more favorably onto alumina surface than the oxygen-cont aining functionality for both the MMA2VP/alumina and MMA4VP/alumina systems .